Four supply sources feed a central grid hub: domestic generation, two import pipelines, and a tanker-delivered LNG import. Each has its own fixed base capacity; the import-dependency slider shifts how much of the country's total capacity comes from domestic generation versus the three import routes combined — a stand-in for a country's real supplier mix. Disrupting a source (sanctions, a technical fault, a route closure) drops its output toward zero over a couple of seconds. When total delivered supply falls short of demand, the strategic reserve — a store of stockpiled fuel or banked capacity — drains to cover the gap. Once the reserve empties, the shortfall shows up directly as regional blackouts: the small consumer nodes across the grid go dark in proportion to the deficit.
delivered = Σ source.capacity·(1-disrupted) · share(importBias)
deficit = max(0, demand − delivered)
reserve -= min(reserve, deficit) · dt (reserve refills slowly when supply exceeds demand)
darkFraction = max(0, deficit − reserveDraw) / demand
- National demand — total load the grid must serve; higher demand leaves a thinner margin against any single disruption.
- Import dependency — left biases capacity toward domestic generation, right toward the three import routes combined; a heavily import-dependent grid recovers less gracefully when one import route is cut.
- Strategic reserve size — how much banked capacity exists to absorb a shortfall before consumers feel it; a bigger reserve buys time to reroute or repair.
- Disrupt buttons — simulate losing one supplier entirely; combine with a high import bias to see why diversification (no single route above ~30-40% of total capacity) is the standard energy-security guideline.
Real-world relevance: this is the logic behind national reserve mandates (strategic petroleum/gas reserves), N-1 contingency planning for interconnectors, and diversification targets that cap how much of a country's energy can come from one supplier or one route.